The treatment of webs of material, especially textile webs, e.g. in the printing of patterns thereof, may utilize a bed or surface upon which the web is supported and cooperating members on opposite sides thereof for the treatment operation, e.g. printing a pattern on the textile web.
Screen printing devices utilizing cooperating members on opposite sides of the web are described, for example, in the aforementioned copending applications.
While the present application is particularly directed to the screen printing of textile webs utilizing a round or flat pattern and a magnetically attracted wiper for pressing the printing ink or coloring matter through the pattern onto the fabric, it is equally applicable to other treatments of flat materials, hereinafter generally referred to as webs, utilizing members on opposite sides of the web which are intended to move relative to the web and the surface upon which the web is disposed. Hence the specific description of textile fabric printing will be understood to include description of corresponding treatments of other materials which require similar movements.
In the printing of textile fabrics, it is known to fasten the textile web on a plate, table or other support member which has generally been mounted at its end and along its sides on a support frame carrying the upper and lower cooperating members. The mounting may be effected by temporary bonding, e.g. via a releasable adhesive. The round pattern (see the aforementioned applications) or a flat pattern, as is known from still earlier screen printing systems, is in the form of a screen having local areas through which the ink or dyestuff can be pressed. The round or flat pattern is shiftable on rails in a longitudinal direction of the elongated table and the printing is carried out sectionwise, i.e. first on one area of the web and then on an adjacent area of the web. Consequently, the pattern can have a size corresponding to the pattern repeat and substantially less than the size of the web to be printed.
In recent years, magnetic systems of the type described in the aforementioned copending applications have been developed to utilize magnetic force for applying the blade, roller or other pressing element against the pattern. For this purpose, below the support plate for the textile web or the printing surface, a magnetic beam or magnetic roller must be provided as a countermember toward which the blade or pressing element is attracted.
It is imperative that this magnetic member follow precisely the displacement of the pattern, which can be a screen printing member and, for flat patterns, also be capable of movement in the longitudinal direc tion relative to the pattern in order to imprint an image thereof on the textile web.
This has posed significant problems in prior art systems.